/Engine/Source/Runtime/Slate/Public/Widgets/Layout/SGridPanel.h
Dynamically add a new slot to the UI at specified Column and Row. Optionally, specify a layer at which this slot should be added.
A reference to the newly-added slot
[FScopedWidgetSlotArguments](API\Runtime\Slate\Widgets\Layout\SGridPanel\FScopedWidgetSlotArguments) AddSlot ( int32 Column, int32 Row, [Layer](API\Runtime\Slate\Widgets\Layout\SGridPanel\Layer) InLayer )